diff --git a/nginx.conf b/nginx.conf
index b9b7dfe..3044a02 100644
--- a/nginx.conf
+++ b/nginx.conf
@@ -76,6 +76,21 @@
             send_timeout 1800s;
         }
 
+        # エージェントチャット: ファイル添付 最大 10MB
+        location /api/core/agent/chat {
+            client_max_body_size 10m;
+            proxy_pass http://backend;
+            proxy_http_version 1.1;
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection $connection_upgrade;
+            proxy_set_header Host $host;
+            proxy_set_header X-Real-IP $remote_addr;
+            proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
+            proxy_set_header X-Forwarded-Proto $scheme;
+            proxy_read_timeout 86400s;
+            proxy_send_timeout 86400s;
+        }
+
         location /api/ {
             proxy_pass http://backend;
             proxy_http_version 1.1;